AR Projection Lens Alignment for Parallel Waveguide Light
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Solution Overview
Problem
Existing augmented reality (AR) devices struggle to provide high-quality virtual images due to variations in the parallelism of light projected from the projection lens, which can result in unclear virtual images when the lens position changes or back focal length is altered.
Innovation Solution
An electronic device equipped with a light sensor to detect the degree of parallelism of light passing through a waveguide, using an actuator to adjust the position of the projection lens relative to the optical axis, ensuring that light is projected in parallel to maintain clear virtual images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the projection lens position is fixed, then the device structure is simple, but the virtual image quality deteriorates when back focal length changes or physical distortions occur
Solution Approach 1:
The patent implements dynamic adjustment of the projection lens position through an actuator that moves the lens along the optical axis. The control unit continuously monitors light parallelism and adjusts the lens position in real-time, transforming a static system into a dynamic one that can adapt to environmental changes and maintain optimal virtual image quality.
Solution Approach 2:
The patent employs a feedback mechanism where the control unit detects the degree of parallelism of light passing through the waveguide and uses this information to automatically adjust the projection lens position. This closed-loop control ensures that the system maintains optimal performance by continuously comparing actual performance with desired performance and making corrective adjustments.
2Measurement precision
If the projection lens position is manually adjusted, then the virtual image quality can be improved, but the ease of operation deteriorates and adjustment precision is insufficient
Solution Approach 1:
The patent implements a self-adjusting system where the device automatically monitors and corrects its own performance. The control unit detects light parallelism and autonomously controls the actuator to adjust the projection lens position without requiring user intervention, enabling the system to self-optimize and maintain high adjustment precision.
Solution Approach 2:
The patent replaces manual mechanical adjustment with an automated electromechanical system. The actuator, controlled by electronic signals from the control unit, substitutes for manual operation, providing more precise and consistent adjustment while eliminating the need for user skill and effort in positioning the lens.
3Measurement precision
If automatic adjustment is implemented, then the adjustment precision and virtual image quality are improved, but the device complexity increases
Solution Approach 1:
The patent integrates multiple functions into a unified automatic adjustment system. The control unit performs both detection of light parallelism and control of the actuator, while the light sensor serves dual purposes in both monitoring and guiding adjustment. This multi-functionality reduces the need for separate components and minimizes overall system complexity despite the added automation capabilities.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device automatically adjusts the projection lens position to maintain light parallelism, providing high-quality, clear virtual images by adapting to physical distortions or environmental changes.
Implementation Method 1
a light sensor configured to detect light passing through the input grating
Implementation Method 2
The input grating is provided on a first surface of the waveguide and comprises a diffraction grating so that light incident on the waveguide through the input grating changes a path within the waveguide
Data Source
AI summary
Provided is an electronic device including an optical engine including a projection lens configured to project light of a virtual image, a waveguide including an input grating on which the light of the virtual image is incident, an actuator configured to adjust a position of the projection lens relative to an optical axis of the projection lens, a light sensor configured to detect light passing through the input grating, a memory configured to store one or more instructions, and a processor configured to execute the one or more instructions to obtain a degree of parallelism of the light detected by the light sensor, obtain, based on the degree of parallelism of the light, a position adjustment value of the projection lens to detect light, and control the actuator to adjust a distance between the projection lens and the waveguide based on the position adjustment value.